Beaver_shots Posted May 9, 2017 Report Share Posted May 9, 2017 New here been lurking on these forums for a while. I have wanted a 720 for a long time and I finally picked one up last month. 86 short bed 4x4. I am a very amateur mechanic and this truck for me about diy and learning a bit more about working on cars. Every one here seems really knowledgeable and friendly compared to a lot of forums so here I am. HI First it shows z24s motor and has the vacuum distributor so I guess this is a carb truck and not TBI? Problem: Starts up okay, choke seems to be working. It will idle fast but when coke opens or when I kick it down with the throttle truck starts sputtering and dies. I can keep it going with peddle. I realize this is a pretty common topic and its been talked about a bunch so sorry for asking dumb questions. First thing I did was cap all the emission lines off except the line to the distributor. That didn't change anything. I discovered that there is a linkage on the carb that is broken from the diaphragm on the drivers side to the side of the choke. I'm guessing this has something to do with controlling the idle? Could this be the whole problem? Or should I be looking at other things? I am planning to swap out the stock crab for an aftermarket Weber at some point but it would be nice to get it running properly before that. Reading here I was thinking this could also be a timing issue with both sides of plugs not firing. Saw a thread suggesting to take off a wire from the distributor assembly.. there is one by it self would that be the one? Any suggestions would be appreciated. I cant really contribute too much to the mechanic talk here but I work in the drone industry and build 3d printers for fun so if you guys got questions about that stuff shoot haha. Thanks 1 Quote Link to comment
datzenmike Posted May 10, 2017 Report Share Posted May 10, 2017 Two wing nuts holding the air filter on.... TBI One wing nut .... carb. There were two style of carbs. I imagine by '86 they were all electronic feedback. Do you have an O2 sender in the exhaust manifold? Is there 5 or 6 wires going to the back of the carb? If so this is what you have. Let me know. 1 Quote Link to comment
Beaver_shots Posted May 10, 2017 Author Report Share Posted May 10, 2017 There is one nut holding the air filter and 4 clamps. There is a wire coming out of the exhaust manifold and I assumed this was an O2 sensor. as for the number of wires to the carb its hard to tell because there have been some changes by previous owners it looks like. Has a round plastic plug and some of those wires have been cut. Looks like currently there is one wire going to the choke and one going to a plug to the passenger side of the coke, also a ground wire for each so 4 total right now. There is a yellow (I think) wire that looks like it might have broken off from the connector. Ill have to look at it when I get home tonight. You're from Vancouver island? I went there once. I met a guy at a bar called maude hunters who had a toe for a thumb. One of the weirdest things I've seen. He said he lost his thumb in a boating accident so they cut off his big toe and put it on for a thumb. Nice guy drank with him most of the night. I'd like to go back up there again some day. 1 Quote Link to comment
captain720 Posted May 10, 2017 Report Share Posted May 10, 2017 If the Carb is to messed up I would personally just go Weber right away, but that's just me and I am new too. Dmike know what's up for sure. 1 Quote Link to comment
Beaver_shots Posted May 10, 2017 Author Report Share Posted May 10, 2017 Yes you are probably right I should just buy a new carb rather than mess around with this set up since the carb is clearly broken. That said I want to diagnose the issue for the sake of my own understanding and yes it would be nice to get it running right sooner. I probably wont have the spare 300 bucks to drop on carb till a couple weeks from now. Second reason I'd like to get it running is because my girl friend was/is pretty pissed I brought home a project lol. I told her I was leaving to go buy a truck the day I picked this up. the last thing she said to me was "this better not be a project car" with that all too familiar look on her face. She knows I have a tinkering habit. So funny story, I looked at the truck and drove it, realized it had an idling issue but bought it anyway (600 bucks) and proceeded to drive it home. The trip was about 45 miles and was going pretty well just giving a little peddle at stop lights. Next thing I know its not wanting to stay running... sputtered out, but I was able to restart it and carry on... died again a few blocks down the road. I'm thinking "shit it has bigger problems and now I got to have it towed". So I call my AAA and they come flat bed it back to my place, my buddy was driving behind me so I ride with him. We get to my place and the flat bed isnt far behind. I see the g/f look out the window as the flat bed rolls up with my tuck on it...shes mad clearly.. just closes the blinds and doesn't come out... I know I'll be getting the silent treatment tonight.. hahaha. Any way I spent about 2 hours the next day trying to get it to fire up so I could be like "see it runs I swear" and no luck... I'm scratching my head and looking it over... then it dawns on me... is there even gas in this thing? I had been so fixated on trying to drive the thing home and what rout to take I failed to even look at the gas gauge. On E.... well maybe its broken? Put a gallon of gas in it from my can and cranked for a few min... fires up. I'm a moron. 1 Quote Link to comment
captain720 Posted May 10, 2017 Report Share Posted May 10, 2017 Yeah, you sound like me. 1 Quote Link to comment
Beaver_shots Posted May 10, 2017 Author Report Share Posted May 10, 2017 I have been thinking about adjusting the idle screw up to keep it running. Just feel like that would be pretty high RPM but to be fair I haven't tired. Also seems to run really bad at low idle like engine shaking a bunch. So yeah I was thinking timing issue or ignition possibly because of that. The guy I bought it from had recently tried working on it after it had been sitting for several years. He threw parts at it. New starter so thats nice plus distributor cap/plugs/wires so who knows if he knew what he was doing. He flat told me he had no idea how to fix things just replaces parts and crosses fingers. I might try adjusting idle tonight. Maybe I should take some pics? Hey you are in WA too eh? I'm out in Stevenson. I looked at a 720 on CL in Yakima before I got this truck. I was going to drive up there but sold it before the weekend rolled around. Side not my 720 needs a trany as well... no reverse :( I am supposed to meet a guy in Eugene this weekend who has a tranny out of 2wd newer truck (cant recall what year he said it was). been talking to him and measuring stuff. he says it should bold right up, my understanding is I might have to adjust the drive shaft. will see I guess. 1 Quote Link to comment
captain720 Posted May 10, 2017 Report Share Posted May 10, 2017 Is it a tranny from a D-21? I just bought a 720 off CL Yakima. 1 Quote Link to comment
captain720 Posted May 10, 2017 Report Share Posted May 10, 2017 Oics are required. 1 Quote Link to comment
captain720 Posted May 10, 2017 Report Share Posted May 10, 2017 Oics are required. 1 Quote Link to comment
Beaver_shots Posted May 10, 2017 Author Report Share Posted May 10, 2017 Yeah I think it is out of a D21. Yakama truck was a few months ago. Was a blue single cab 4x4... 84 I think. 1 Quote Link to comment
captain720 Posted May 10, 2017 Report Share Posted May 10, 2017 Oh I bought a blue, 2wd 86. It has a thread but I haven't made too much progress since spring break ended. 1 Quote Link to comment
datzenmike Posted May 11, 2017 Report Share Posted May 11, 2017 The carb has a solenoid in the primary jet that constantly adjusts the mixture using several sensors and an O2 sensor for feedback. There is a computer under the driver's seat to control it. It also has a 'limp home' mode should there be a failure. This forces a rich condition and it runs like the choke is on all the time. A lot can go out of wack with it. Here's where the wires go, maybe you can get them connected. If not it will never run properly. This is a carb but it's very close to EFI in function. 1 Quote Link to comment
Beaver_shots Posted May 11, 2017 Author Report Share Posted May 11, 2017 hmm... I could put it back to that configuration but the question is why did someone hack it up to start with? Its like they were trying to bypass a wiring issue. That kind of leans me toward just waiting and putting an aftermarket carb rather than dig into all this wiring crap. if they were just cut I'd try putting it back, but it looks like somebody decided to do their own wiring and cut into the harness. I hate when people do that. Just run a new wire if you have a fault in the harness. So the question I have now is what happens when I pop a carb on it... should I just disconnect the o2 sensor? Does it even matter? Dose the computer control anything besides the carb stuff? Like say the fuel pump? Can I just unplug it? Pics I realize there are some uncapped lines in this last photo but that was taken while I was capping. As for the egr valve thing that connects to the exhaust manifold... I can just leave that on and cap the vac lines to it? I thought that was what I read in another thread. I might post a video of it "running" if anyone is interested haha. 1 Quote Link to comment
captain720 Posted May 11, 2017 Report Share Posted May 11, 2017 Cap egr valve, I think my fuel pump is getting.power from the heater relay 1 Quote Link to comment
Lockleaf Posted May 11, 2017 Report Share Posted May 11, 2017 Ecu only controls the carb. When swapping to an aftermarket carb, you will only need the choke heater wire. Everything else at the carb is useless. Yes you can cap the vacuum lines on the egr. 1 Quote Link to comment
captain720 Posted May 11, 2017 Report Share Posted May 11, 2017 Don't lose that choke relay wire either, mine is getting power from a coil still. 1 Quote Link to comment
Beaver_shots Posted May 11, 2017 Author Report Share Posted May 11, 2017 Yes the choke is working currently I believe so Ill make sure to keep that and the ground. Looking at weber kit on ebay.. any tips on buying the kit? https://www.ebay.com/p/?iid=331335363921&lpid=82&&&ul_noapp=true&chn=ps This is what I am thinking. Its foggy to me with this 85 and 1/2 86 stuff. I assume for this truck any kit that includes 85 will be fine in terms of the adapter plate fitting? as for the d21 tranny I think I saw you had some experience with this captain720. Thoughts? also once its running I want to do some preventative care for the engine. Aside from changing the oil what are some things that would be good to look at? 1 Quote Link to comment
captain720 Posted May 11, 2017 Report Share Posted May 11, 2017 Retorquing head bolts is very important, also it will likely have a bunch of garbage in the heater intake. The CVs like to wear out and they are not much fun to replace, just look at the rubber boots and see how far gone they are. I had to do the ones on my 4wd, it wasn't that enjoyable. I think there is thread that I saw yesterday with some info on D21 tranny swaps, other rats will know more than me. I think there is a stock 4wd tranny in my local wrecking yard right now. But it looks like you are over 4 hours away as I live on the dry side. 1 Quote Link to comment
Beaver_shots Posted May 11, 2017 Author Report Share Posted May 11, 2017 Good call. I looked at the CV boots when I bought it and they look in really good shape maybe replaced at some point. The trans I'm looking at is out of an 89 D-21 2w drive. Its all the way down in Eugene, but I'm going down there this weekend anyway because the g/f's mom lives down there. I'm sure she is going to love it when I cram an oily transmission into the truck of my Audi on the way back hahaha. The dry side hahah so true. I was born and raised in The Dalles and my Grandmother use to live in yakama spent a bit of time out there. Am not opposed to the idea of driving up for a proper transmission. Whats the verdict from the community... would I be better off with one out of an 89? My gut says yes but it should be noted that my intuition is typically wrong. 1 Quote Link to comment
captain720 Posted May 11, 2017 Report Share Posted May 11, 2017 I would call around check cars-part. I will check with my wrecking yard to see if they still have e it for you. I don't think there are many rats around here. 1 Quote Link to comment
Beaver_shots Posted May 11, 2017 Author Report Share Posted May 11, 2017 I trolled the yards in Portland for a weekend couple weeks ago. I discovered that a lot of the yards in portland use an internet system to track stuff and can see what each other have listed so that is kind of cool Its kind of like this one but this seems to find less stuff: http://www.a-1truckparts.com/used-auto-parts-finder/ No trans around here but its good to look every week or so I imagine. I ended up getting an ignition switch assembly from a guy out there for 40 bucks with key. Mine is hashed from an attempted theft. They must have sat there with a screwdriver in the ignition for a long time because its disintegrated. Yeah if they still have the tranny I'll have to consider it an option. I do feel like a newer one would be more dependable in the long term. 1 Quote Link to comment
captain720 Posted May 11, 2017 Report Share Posted May 11, 2017 I think the D21 2wd probably has a higher fist gear, but I think the one over here is rather high milage. It should bolt up,you will need to change the drive shaft between the tranny and the divorced transfer case. (Thank God ours are divorced). Also if you have the tranny out you must absolutely check your clutch. 1 Quote Link to comment
Beaver_shots Posted May 11, 2017 Author Report Share Posted May 11, 2017 I think swapping the tranny is actually going to be a job for my brother in law. He has his own mechanic shop so pulling the engine and swapping trans shouldnt be that big a deal for him. I dont have a picker and I dont want to buy one. Will just put a new clutch at the same time I think. 1 Quote Link to comment
Beaver_shots Posted May 11, 2017 Author Report Share Posted May 11, 2017 I think the D21 2wd probably has a higher fist gear, but I think the one over here is rather high milage. It should bolt up,you will need to change the drive shaft between the tranny and the divorced transfer case. (Thank God ours are divorced). Also if you have the tranny out you must absolutely check your clutch. So is adjusting a drive shaft length something any old machine shop can do? I think they do machine work at the NAPA in the dalles. 1 Quote Link to comment
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